Polyurethane foam reconstitution

Abstract

This application describes a method of rejuvenating reticulated polyurethane materials, particularly those containing ester-type linkages which have been hydrolyzed after being exposed to moisture containing hydrocarbon fuel and/or highly humid environments. The process consists of treating the polyurethane with cross-linking compounds, such as diisocyanates and polyfunctional epoxy compounds.

What is claimed is: 
     
       1. The process of treating reticulated polyester urethane foam materials positioned in a fuel tank, said foam containing molecular linkages which have undergone hydrolysis and partial reversion comprising passing a reconstitution diisocyanate or polyfunctional epoxy compound through the fuel tank, and contacting the hydrolyzed polyurethane foam with said reconstitution material to produce a reconstituted foam structure in situ. 
     
     
       2. The process of claim 1 including the step of attaching the cleaved portions of the polyurethane through the diisocyanate or polyfunctional epoxy material. 
     
     
       3. The process of claim 1 wherein the reconstituting materials are combined with fuel and the mixture is placed in the fuel tank to reconstitute the foam. 
     
     
       4. The process of claim 1 wherein the concentration of diisocyanate or polyfunctional epoxy compound to reticulated polyurethane is about 0.25% to about 5%. 
     
     
       5. The process of claim 1 wherein the foam is treated with the reconstituting material at a temperature of about 50 to about 100° F. for about 1 to about 10 hours. 
     
     
       6. The process of claim 1 wherein the diisocyanate is selected from a group consisting of toluene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, trimethylhexamethylene diisocyanate, and mixtures thereof. 
     
     
       7. The process of treating reticulated polyurethane foam materials positioned in a fuel tank, said foam containing ester linkages which have undergone hydrolysis and partial reversion comprising treating the hydrolyzed polyurethane material in the fuel tank with a polyfunctional epoxy compound selected from a group consisting of diglycidyl ether of bis(4-hydroxyphenyl)dimethylmethane, polyglycidyl ether of tetraphenylene ethane, tetraglycidyl methylene dianiline, bis (epoxy cyclo pentyl) ether, tetra (p-glycidyloxyphenyl) ethane, triglycidyl p-aminophenol, and mixtures thereof, and forming a reconstituted foam structure in situ.